Roundness measuring device, method and program for measuring roundness

Abstract

A roundness measuring device includes: an eccentric position calculation unit calculating, based on a measured distance and a measured angle, a distance between a axis of the measured object and a rotation axis as an eccentric distance, and calculating an angle formed between the detection line and a line segment connecting the rotation axis and the axis of the measured object as an eccentric angle; and a measurement correction unit correcting the measured distance based on the eccentric distance, the eccentric angle, the measured angle, a radius of the measured object, and a length from the center to the surface of the detector unit, and correcting the measured angle by adding a correction angle to the measured angle, the correction angle being formed between the detection line and a line segment connecting the rotation axis and a contact point where the measured object and the detector unit come in contact with one another.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-135703, filed on May 22, 2007, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a roundness measuring device, method and program for measuring the roundness of a measured object.[0004]2. Description of the Related Art[0005]Roundness measuring devices are used to measure the roundness of columnar or cylindrical workpieces (measured objects). Such roundness is measured by mounting a workpiece on a turntable (centering table), rotating the turntable (table rotation type) or revolving a stylus itself around the workpiece, and then tracing the round surface of the workpiece (such as the outer or inner surface) with the stylus. A roundness measuring device of table rotation type obtains measurements based on a displa...

AI Technical Summary

Benefits of technology

The present invention provides a roundness measuring device that can accurately measure the roundness of an object. The device includes a rotation unit, a detector unit, and a measurement acquisition unit. It can measure the distance between the rotation axis and the detector unit, as well as the angle between the detection line and the object. An eccentric position calculation unit can also be used to calculate the distance between the rotation axis and the detection line, as well as the angle between the detection line and the object. A measurement correction unit can then correct the measured distance and angle based on the eccentric distance, the angle, the object's radius, and the length of the detection line. This device can accurately measure the roundness of an object and eliminate any errors in the measurements.

Problems solved by technology

Accordingly, if the workpiece is eccentric with respect to the rotation axis of the centering table, some occasions may arise where the contact point is not located on a predetermined axis depending on the radius of the stylus, which would lead to errors in measurements.

Such error problems would notably occur when a measurement is performed on a workpiece in an eccentric position that has a smaller radius than that of the stylus.

Images